The basic objective of the research is to obtain a clearer knowledge of the cellular mechanisms involved in retinal degenerations caused by light exposure in the albino rat and by inherited retinal disease in the Royal College of Surgeons strain of rat. These two cases have been proposed as animal models for the class of human degenerative diseases of the retina, retinitis pigmentosa. Thus, a related objective is to more firmly establish the resemblance of these animal models to retinitis pigmentosa. The focus of the proposed work will be to probe the degenerating visual mechanisms as they contribute to threshold and receptive field properties, light adaptation, dark adaptation and spectral sensitivity by using single unit recordings from the optic tract and lateral geniculate nucleus and by recording electroretinograms and the early receptor potential. An attempt will be made to assess higher visual pathway function independent of retinal function by recording responses of lateral geniculate nucleus cells to electrical stimulaton of the optic nerve. An attempt will be made to prove the linkage between retina and lateral geniculate nucleus by dual recording from the retina and lateral geniculate nucleus. In addition, behavioral testing for visual capacity will be done.